1. Field of the Invention
This invention relates to an improved control device of the differential pressure type and to a method of making the same.
2. Prior Art Statement
It is known to provide a control device having a housing means provided with an actuator chamber separated from a pressure differential chamber by wall means having opening means therethrough receiving an axially movable actuator pin that transmits axial movement of a movable part in the pressure differential chamber to the actuator chamber. For example, see the U.S. Pat. No. 4,289,963 to Everett, wherein an optical switch means is disposed in the actuator chamber of the control device and the actuator pin has an interrupter means for actuating the optical switch means when the movable part moves the actuator pin to a certain position relative to the housing means.
It is also known to cause relative movement between a Hall effect transducer means and a magnet means for operating the transducer means through the movement of a wall that has a pressure differential acting across the same. For example, see the U.S. Pat. Nos. 4,254,395; 4,326,419 4,340,877 and 4,352,085 to Herden.
It is also known to mount two permanent magnets on spaced apart portions of a bifurcated member so that the Hall effect transducer means is disposed between the magnets, the bifurcated member being movable relative to the fixed transducer. For example, see FIG. 5 of the Honeywell Microswitch Division Publication No. 84-05704-A 980 and FIG. 7 of the aforementioned U.S. Pat. No. 4,352,085 to Herden.